Sheet fed digital printers are capable of storing only limited numbers of different types of receivers. However, with increased use of digital image capture, image editing and digital image and document creation, there is an increased demand for prints that have specific print lengths that are not typically stored in such sheet fed printers.
This demand can be met by manually feeding such printers with receivers that have the specific print length. This adds significant costs to the process of printing using the requested receiver in that less frequently used receiver must be acquired and manually loaded before printing and because the manual loading process includes expenses for the labor required to locate and to load such receiver into the printer. It will be appreciated that such manual processes can also lead to delays in printing.
Alternatively, this demand can be met by cutting receiver to the specific receiver length. Typically, this is accomplished by printing on a stored receiver that is larger than the required print length and cutting excess length from the receiver during one or more finishing operations. Such finishing requires manual processes or the provision of equipment that is capable of cutting longer prints to the determined length. The use of either form of finishing can add significant equipment or processing costs and/or can add significant processing time to the fulfillment of the print order.
In still another alternative, print orders for prints that have specific print lengths that are not typically stored in such sheet fed printers. However, such an approach requires a custom measuring and cutting operations for each receiver. Printing and cutting long sheets poses several limitations. First, rolls of paper are heavy and hard to handle. The use of such roles precludes rapidly changing from one type of paper to another. Moreover, an entire print would have to be made from a single type of paper. Having a print engine and process capable of printing on sheets of paper that can be bound allows using different papers for special effects at different portions of the print. For example, a cover can be printed using a heavy black paper around the spine portion and a different color paper where the title and author are to be printed, thereby creating a decorative effect. Textured papers can also be blended with non-textured papers for an artistic effect.
Accordingly, what is needed is a method for printing and a printer that enable readily available stored receivers in a printer to be used to create prints that have specific lengths without requiring precutting or finishing operations.
What is also needed in the art is a method for operating a printer and a printer that can generate long prints using combinations of sections of available stored receivers in a printer.
One attempt to meet this second need in an electrophotographic printing system is described in U.S. Pat. No. 6,577,845 entitled “End to End Binding Using Imaging Material and Continuous Sheet Printing” issued to Stevens on Jun. 10, 2003. This patent describes using imaging material binding techniques to simulate continuous sheet printing with single sheets of printed receiver. In accordance with the methods described therein, imaging material is applied to a binding region along the trailing edge of a first printed sheet. The trailing edge of the first printed sheet and the leading edge of a following second sheet are overlapped and the imaging material is activated to bind the sheets together. This process may be repeated for successive sheets to form one continuous sheet. The technique described therein is said to be capable of implementation, for example, in a stand alone appliance used in conjunction with a conventional single sheet printer, as in integrated printing device or through a computer readable medium used to control operations in one or both of these devices.
FIGS. 1A, 1B and 1C show examples of the bound sheets created by the '845 patent adapted from FIGS. 13, 14 and 15 of that patent. These figures are said to show three different configurations for overlapping first, second and third sheets. As is described in the '845 patent, imaging material is applied to each sheet 2, 4 and 6 to form the desired print image 8, if any. In the configuration of FIG. 1A, imaging material is also applied for binding to the leading edge 10 of each following sheet 4, 2 which is lapped under the trailing edge 12 of each leading sheet 6, 4. In the configuration of FIG. 1B, imaging material is applied for binding to the trailing edge 12 of each leading sheet 6, 4 which is lapped under the leading edge 10 of each following sheet 4, 2. In the configuration of FIG. 1C imaging material is applied for binding to the leading and trailing edges 10 and 12 of the middle sheet 4 which is lapped under the trailing edge of the leading sheet 6 and the leading edge of the following sheet 2.
As will be observed from FIGS. 1A, 1B, and 1C, in each of the prints formed in accordance with the method shown in the '845 patent, there is a step S at every overlapping edge. Each step S has a step drop off height that is at least as tall as a thickness of the edge of the overlapping receiver and any toner image recorded thereon. Generally, speaking, the thickness of a paper type receiver can be between 81 um and 450 um depending on the weight of the paper. Further, in electrophotographic printers, a layer of toner is applied to the surface of such receiver, further increasing the thickness of the overlapping print by a range of between about 10 um and 50 um after fusing. While these ranges are provided by way of example only, it will be appreciated that a step having a height of at least about 100 um can be expected and that the step height may be substantially greater in many cases.
A step of such height detracts from the overall appearance of the printed image by providing a vertical or horizontal line extending across an image in which a difference in relief is observable from all angles of viewing, and in which an unprinted edge of the overlapping sheet is viewable from many angles of viewing. Both of these conditions detract from the appearance of a combined print. Such artifacts are typically not acceptable to consumers who expect prints to be recorded on a continuous receiver.
A step of such height also creates a catch point that can cause damage to the bound sheets if mechanically engaged while the combination print is being moved.
What is needed therefore are improved printing methods and systems that can join receivers to form a combination print having a length that is greater than a length of any available receiver but with a more durable configuration and a better appearance.